Single lever control mechanism

ABSTRACT

A single lever control mechanism for operating a plurality of control elements which includes a base member, a main control member supported for revolving movement relative to the base member about a member which is spaced from the base member and means for preventing rotation of the main control member about an axis which coincides substantially with the center of said member about which the main control member is revolvable and is substantially normal to the base member, the main control member being operatively associated with at least two control elements which are spaced apart and operatively connected with operators such as moveable valve elements. In preferred embodiments, guide means is provided which functions in conjunction with the configuration of the main control member and the revolving movement of the main control member to automatically, progressively, simultaneously and proportionately decrease the flow of the actuating medium through one operator as the flow of actuating medium through another operator is increased and vice versa. In preferred embodiments, the guide means also arrests tilting movements of the main control member to prevent the exertion of excessive forces upon the operators by actuation of the single lever.

United States Patent 1191 Pilch Apr. 2, 1974 '[22] Filed:

[ 1 SINGLE LEVER CONTROL MECHANISM John S. Pilch,'Ware, Mass.

[73] Assignee: Ware Machine Works, Inc., Ware,

-Mass.

June 14, 1972 211 Appl. N6: 262,550

[75] Inventor:

[5 6] References Cited UNITED STATES PATENTS 1,499,640 7 1924 Copeland 74 501 M 3,191,455 6/1965 Fuqua et al. 74 501 M 3,225,621 12 1965 Augunas 1 1 -74/501 M 3,253,481 5/1966 Warhol 74/501 M 3,369,427 2 1968 Brighton et al. 74 501 M 3,550,470 12 1970 Brighton et al. 74 501 M 3,625,085 12/1971 Shrode 74 501 M 470,668 3 1892 Fisher 287/12 x 2,679,678 6/1954 Stephan 200/6 A 3,049,939 8 1962 Beard 1 74/526 3,541,877 11 1970 Houk 74/471 xv 3,705,519 12 1972 Sjoo 74/471 xv Primary Examiner-Allan D. Herrmann [57] ABSTRACT A single lever control mechanism for operating a plurality of control elements which includes a base member, a main control member supported for revolving movement relative to the base member about a member which is spaced from the base member and means for preventing rotation of the main control member about an axis which coincides substantially with the center of said member about which the main control member is revolvable and is substantially normal to the base member, the main control member being operatively associated with at least two control elements which are spaced apart and operatively connected with operators such as moveable valve elements. In preferred embodiments, guide means is provided which functions in conjunction with the configuration of the main control member and the revolving movement of the main control member to automatically, progressively, simultaneously and proportionately decrease the flow of the actuating medium through one operator as the flow of actuating medium through another operator is increased and vice versa. In preferred embodiments, the guide means also arrests tilting movements of the main control member to prevent the exertion of excessive forces upon the operators by actuation of the single lever.

42 Claims, 27 Drawing Figures PATENTEUMR 2 I974 sum 01 or 12 D (D N FIG! GROUND LEVEL PATENTEUMR 2:914 3.800 615 sum 03 or 12 PATENTEDAPR 2mm 3.800.615

sum 0unF12 BOOM UP 65 FIG? PATENTED APR 2 I974 SHEET 07 0F 12 PATENTEUAPR '2 I974 sum as UF 12 Y GI 123m 20mm PATENIEDAPR 2 I974 sum 0: 1 or 112 FIG. I5

FIG. 17

PATENIEBAPR 2 I974 sum 10 or 1'2 mv UN? 228 zoom Em: @256 m 230D 2Com .EMJ @ZtSM 'PAIENIEDAPR 21914 3,800,615

sum 110F1 2 PATENIEDAPR 2mm I 3,800,615

sum 12 or 12 I23 I07 I20 1 SINGLE LEVER CONTROL MECHANISM BACKGROUND OF THE INVENTION In many types of implements, for example, a backhoe or trencher, there are several hydraulic motors which function to move aplurality of elements of the implement. It is often desirable to move several of these elements at the same time so as to reposition the digging bucket with a minimum of time. In a backhoe, there may be either one or a pair of hydraulic motors which move or swing the boom laterally left or right, a second hydraulic motor which moves the boom vertically, a third hydraulic motor which operates the dipperstick at the end of the boom and a fourth hydraulic motor which operates to move the bucket on the end of the dipperstick. Each of these hydraulic motors incorporates the use of an operator or valve which feeds and/or withdraws fluid from the motor as it becomes necessary. A

It is desirable in 'many instances that several of the functions of a backhoe be performedat approximately the same time. For example, in many instances, it is adv vantageous if the boom is swung laterally at the same time as it is raised'or lowered and consequently the use of a single lever control mechanism to control the swing hydraulic motor or motors and the lift hydraulic motor for the boom is advantageous. Similarly, in many instances, it is advantageous to move the dipperstick vertically about the end of the boom while at the same time operating the bucket on the end of the dipperstick to drive the bucket into the ground to dig the earth. Therefore, it is desirable to provide a control system which utilizes a single lever control-mechanism for controlling the hydraulic motor for moving thedipperstick vertically about the end of the boom and for controlling the hydraulic motor for operating-the bucket on the end of the dipperstick.

Single lever control mechanisms are disclosed in U.S. Pat. No. 2,979,081 which issued to Messrs. McCanse and Ager Apr. 11, 1961, U.S. Pat. No. 3,131,575 which issued to Mr. Clingerman May 5, 19 64, and U.S. Pat. No. 3,388,609 which issed to Mr. Miller June 18, 1968.

One problem which exists in the McCanse et al. and

Clingerman control mechanisms is that there are several pivotal interconnections, each of which must have w some tolerance and consequently there is considerable stances sensitive to slight adjustments and must be moved in a very accurate manner, this looseness or play in the valve control mechanisms often creates a problem.

One problem which exists in the Miller mechanism is that, in an attempt to eliminate the play or looseness in the pivotal interconnections, Miller utilizes exteriorly screw-threaded bolts positioned in interiorly screwthreaded passages so that during movement of the valve control elements about the pivotal connections, it is necessary for the control elements to traverse the screw-threads of the bolts and this creates problems of friction and wear of the screw-threads as well as relatively high costs of fabrication of the screw-threaded elements and of construction and assembly of the control mechanism.

Another problem which exists with said McCanse, Clingerman and Miller control mechanisms is that to control two hydraulic motors, the backhoe operator must make two different successive motions with the single lever whereas with a control mechanism embodying thepresentinvention only one continuous motion of the single lever is necessary.

Another problem which exists in all prior art single lever controls of which I am aware is that no means is provided which, when the operator actuates the lever, automatically, progressively,"simultaneously and proportionately controls the increase and/or decrease of the flow of the actuating medium through the plurality of operators to and from the plurality of hydraulic motors for example.

Another problem which exists in all prior art single lever control mechanisms of which I am aware is that they contain two main control members which are more expensive to produce and more complicated to operate, whereas a control mechanism embodying the present invention uses only one main control member and is easy to operate.

Another problem which exists in all prior art single lever control mechanisms of which I am aware is that excessive forces are exerted upon the operators by ac- SUMMARY OF THE INVENTION One object of this invention is to provide a new and improved single lever control mechanism which may be used to actuate a plurality of operators for a plurality of devices such as hydraulic motors.

Another object is to provide such a control mechanism which may be easily and accurately controlled by the operator of a machine by manual movements of the single lever.

A further object is to provide such a control mechanism which stands up in prolonged use and does not require frequent repairs or replacement of parts.

Still another object is to provide such a control mechanism which is economical to manufacture and to install on the machine which is to be controlled by the plurality of operators.

Another object is to provide such a control mechaniism which, upon actuation of the lever by the operator of the machine, automatically and selectively controls the increase and/or decrease of the flow of the actuating medium through a plurality of operators to and from a plurality of devices such as hydraulic motors for example. I

Another object is to provide such a control mechanism which has only one main control member so that by one motion of the single lever one or a plurality of functions may be performed by the operator.

A further object is to provide such a control mechanism with guide means which functions in conjunction with the configuration of the main control member and 3 Another object is to provide such a control mechanism with guide means for stopping the tilting movements of the main control member about the means for supporting it for revolving movement to prevent the exertion of excessive forces upon the operators by actuation of the single lever.

Yet another object is to provide such a control mechanism with means for relocating the position of the single control lever with respect to the main control member.

Another object is to provide such a control mechanism with means for relocating at least one of the control elements relative to the main control member so that, for example, the operation of the swing left and swing right valve spools in response to movement of the single control lever may be reversed.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings.

According to one aspect of the present invention, a

control mechanism is provided which includes a main control member, means for supporting the main control member for revolving movement about a member which is spacedfrom the base member, means for preventing rotation of the main control member about an axis which coincides substantially with the center of the member about which the main control member is revolvable and is substantially normal to the base member, at least two spaced apart control elements, means for pivotally securing corresponding ends of said control elements to the main control member at localities which are spaced from each other and from the means for supporting the main control member, means for connecting the opposite ends of the control elements to operators, and a control lever mounted on the main control member for revolving the main control member about the means for supporting the main control member, thereby to actuate the control elements and the re spective operators which are connected to them.

According to another aspect of the invention, means is also provided for adjusting the spacing of the means for supporting the main control member relative to the base member.

ln'one embodiment of the invention the means for supporting the main control member for revolving movement comprises a ball-like type of universal joint, the universal joint being associated with an end of a support member and with the main control member.

In one embodiment each of the means for pivotally securing the spaced apart control elements to the main control member comprises a ball-like type of universal joint and, the centers of the ball-like type universal joints are located substantially in a single plane which extends through the centers of said ball-like type universal joints and through the center of the ball-like universal joint which constitutes the means for supporting the main control member for revolving movement.

In one embodiment the ball-like universal joints are located in bearings formed in the main support member and a portion of each housing comprises moveable means for adjusting the fit between the ball-like member of the universal joint and the bearings.

In another embodiment. the ball-like type of universal joints are located between the main control member and the base member.

In another embodiment, a pin type universal joint, instead of a ball-like type is substituted for one or more of the aforesaid ball-like type universal joints.

In a preferred embodiment, each control element includes means for adjusting its length.

Each control element may comprise a flexible cable, a rigid link or any equivalent connecting element.

The means for preventing rotation of the main control member may comprise a slotted guide member attached to the base member and a member which projects laterally from the main control member into the slot of the guide member, the projecting member moving longitudinally of the slot as the main control member is revolved. Other means may be used including that shown in FIGS. 9 and 10 of the drawings.

In one preferred embodiment guide means is provided which functions in conjunction with the configuration of the main control member and the revolving movements of the main control member to automatically, progressively, simultaneously and proportionately decrease the flow of the actuating medium through one operator as the flow of actuating medium through the other operator is increased and vice versa.

In one embodiment the guide means also functions to stop the tilting movements of the main control member about the means for supporting it for revolving movement to prevent the exertion of excessive forces upon the operators by actuation of the single lever.

In one embodiment, means is provided for relocating the position of the single control lever with respect to the main control member. 1

In one embodiment, means is provided for relocating at least one of the control elements relative to the main control member so that, for example, the operation of the swing left and swing right valve spools in response to movement of the single control lever may be reversed.

The main control member may include substantially arcuate peripheral edge portions of either 360 or of about 180 and the guide means may include a portion of the base member such as its upper plane surface for engagement with said arcuate peripheral edge portions of the main control member when the main control member is revolved. The base member may also include one or more raised portions for engagement with the arcuate peripheral portions of the main control member to stop or limit tilting movements of the main control member towards the base member at the raised portions and the heights of the raised portions may be adjustable.

The main control member may also include nonarcuate peripheralportions such as the configurations shown in FIGS. 15 to 17 of the drawings to obtain other controls of actuation of the operators.

In addition, the guide means may comprise a member mounted above the main control member which may be an arcuate member of 360 or an arcuate member of about 180 as shown in FIGS. ll, 18 and 19 of the drawings. These guide means may also carry position indicating indicia such as BOOM DOWN, etc.

The guide means may also comprise a member which is mounted between the base member and the main control member as shown in FIG. 12 of the drawings which may also carry position indicating indicia.

The guide means may also comprise contoured or raised portions of the surfaces of the base member and of the other guide means described above which contact the arcuate peripheral edge of the main control member during its revolving movements, likewise the guide means may comprise contoured or raised portions of the arcuate peripheral edges of the main control member for contact with plane surface of the guide means during revolving movements of the main control member.

The control mechanism may also comprise an indicia carrying ring which is located between the base member and the main control member when the main control member is in neutral position but through the central opening of which the periphery of the main control member may be moved when it is revolved.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side elevational view of a trencher or backhoe which includes a single lever control mechanism embodying this invention;

FIG. 2 is a slightly enlarged top plan view of the apparatus shown in FIG. 1 with parts broken away;

FIG. 3 is a fragmentary side elevational view similar to FIG. 1, but on an enlarged scale of certain parts of the means for swinging the boom laterally relative to the support; 1

FIG. 4 is a top plan view of one embodiment ofa single lever control mechanism embodying this invention;

FIG. 5 is a section taken on the line 5- 5 of FIG. 4, showing the control inits neutral position; I

FIG. 5A is a reduced section. taken on the line 5A5A of FIG. 5;

FIG. 6 is a section similar to FIG. 5, but with the main control member actuated with the numeral 3 lowered to BOOM DOWN position;

FIG. 7 is a section similar to FIG. 5, but with the main control member actuated with numeral 7 to BOOM UP position;

FIG. 8 is a section on the line 8--8 of FIG. 4 with the numeral 2 of the main control member actuated to "SWING LEFT-BOOM DOWN" position to splitthe flow of the actuating fluid equally between SWING LEFT and BOOM .DOWN operators;

FIG. 9 is a top plan view of another embodiment of single lever control mechanism showing a modified means for preventing rotation of the main control member; I

FIG. 10 is a side elevational view of the embodiment shown in FIG. 9;

FIG. 11 is a side elevational view, partly broken away and shown in section of a control mechanism embodying a modified guide means and position indicating ring, the main control member being shown in full lines in its neutral position and in dot-dash lines when actuated to engage the guide and stop means;

FIG. 12 is a side elevational view partly broken away and shown in section of a control mechanism embodying another modified guide means and position indicating ring with the main control member shown in full lines in its neutral position and in dot-dash lines when actuated to engage the guide and stop means;

FIG. 13 is a diagramatic view showng two valve spools, the housing being shown in section, and flexible cables connecting the valve spools to the spaced control elements which are actuated by the main control member, the main control member being in a position 6 to equally split the flow of fluid between SWING LEFT and BOOM DOWN operators or valve spools;

FIG. 14 is a view similar to FIG. 13 but with the main control member actuated to BOOM DOWN" position;

FIG. 15 is a top plan view ofa modified main control member;

FIG. 16 is a top plan view of another modified main control member;

FIG. 17 is a top plan view of still another modified main control member;

FIG. 18 is a top plan view of a modified control mechanism embodying the invention;

FIG. 19 is a section taken on the line I9l9 of FIG. 18 showing the main control member in neutral position;

FIG. 20 is a section like FIG. 5, but showing the use of pin-type universal joints instead of the ball-like type universal joints shown in FIG. 5;

FIG. 21 in a view like FIG. 13, but showing links connecting the valve spools to the spaced control elements instead of the flexible cables, shown in other views;

, FIG. 22 is a perspective view of the pin type universal joint shown in FIG. 20;

FIG. 23 is a section taken on the line'23-23 of FIG.

24 showing another embodiment of single lever control 7 DESCRIPTION OF THE PREFERRED EMBODIMENTS THE EMBODIMENTS OF FIGS. 1 T010, 13 AND 14 Referring now to the drawings, wherein similar reference characters designate corresponding parts, while the invention is broadly applicable to single lever control mechanisms for other uses, it is shown in the drawings as applied to a backhoe or trencher.

The term universal joint as used herein includes a ball type universal joint which operates in a socket as shown in FIGS. 5 to 14, 18, 19 and 21 of the drawings, a pin type universal joint which comprises a plurality of pins as shown in FIGS. 20 and 22 of the drawings and a ball-type universal joint which includes grooves as shown in FIGS. 23 to 26.

In FIGS. 1 to 3 of the drawings, a backhoe or tren- I cher is shown in which a bucket 1 is pivotally connected to the remote end of a dipperstick 2 which, in turn, is'pivotally connected to the remote end of a boom 3. I

The backhoe comprises a first support 4 to which a second support 5 is pivotally connected by the substantially vertical pivots 6 and 7.

The support 4 is supported in a fixed position in relation to the ground by the stabilizers 8 and 9 which arev The first support 4 is detachably connected to a tractor mounting or platform 12 by means of the hitch elements 13 and 14 of the first support. Each hydraulic motor comprises a double acting piston or ram and cylinder which is actuated by an hydraulic system, the hydraulic power for which is provided by the tractor as is well known in the art.

The second support and the boom 3 which is pivotally attached thereto at 3a (FIG. 1) are moved or swung in a substantially lateral or horizontal direction relative to the first support 4 by a pair of hydraulic motors 15 and 16 (FIG. 2), which are pivotally connected at their ends to the first support 4 by pivots 17a and 18a and at their other ends to the second support 5 by means of the plate 19 which is welded to the second support and by the two link chains 20 and 21 which are associated with the piston rods 15a, 16a of the hydraulic motors l5 and 16 respectively. As shown in FIGS. 2 and 3, the chain 20 comprises a link 200 which is pivotally connected at 19a to the plate 19 and a pair of links 20b which are pivotally connected at 20c to the link 20a and are pivotally connected at 200' to a block on the end of the piston rod 15a. The chain 21 comprises similar links and pivotal connections for actuation by the piston rod 16a. Stops 19b (FIG. 2) are provided on the plate 19.

Since the operation of such means for swinging the second support and boom in a lateral or substantially horizontal direction relative to the first support are described in my U.S. Pat. No. 3,042,236, it will not be described further in this application.

The lateral swinging of the boom may also be accomplished by a single rotary type hydraulic motor cylinder as disclosed at 21 in said McCanse patent.

The boom is moved vertically up and down about the pivotal connection 3a by the hydraulic motor 23 which is pivotally attached to the second support at 23a and to the boom at 23b.

The single lever control mechanism disclosed herein functions to control the flow of actuating medium, such as oil, through operators or valve spools to and from the hydraulic motors 15, I6 and 23 thereby to swing the boom laterally left or right and to move the boom vertically, either individually or simultaneously.

The dipperstick 2 is moved about the pivotal connection 3b by the hydraulic motor 25 which is pivotally attached to the boom at 25a and to the member 26 at 25b, the member 26 being attached to the dipperstock 2. The bucket l is pivotally attached to the dipperstick 2 at 2a and it is moved about said pivot by the hydraulic motor 28 which is pivotally connected at 28a to the member 26 and at 28b to the linkage 29 as is well known in the art.

A second single lever control mechanism similar to the control mechanism disclosed herein may be added to control the flow of actuating medium through operators or valve spools to and from the hydraulic motors 25 and 26 thereby to move the dipperstick and the bucket about their pivotal connections to the boom and dipperstick either individually or simultaneously.

In the embodiment shown'in FIGS. 1 to l0, l3 and 14, the control mechanism comprises the base member 30 (FIG. 5) which is'supported by a structure 31 (FIG. .1) whichis attached to the first support 4. The seat 32 is mounted on the structure 31 and ispositioned where the person who is operating the backhoe may grasp the knob 33a of the lever 33.

The lower end of the lever 33 is exteriorly threaded, is received in an interiorly threaded passage (not shown) in the main control member 35 and is held in adjusted position by the wing nut 34 (FIG. 8). A second interiorly threaded passage 36 (FIGS. 4-8) may be provided in the central element 40 so that, if desired, the control lever may be placed therein rather than in the first interiorly threaded passage as shown in the drawings.

The main control member 35 is disc-like when viewed from the top and the bevelled portion 35a of its periphery may be provided with numerals from I thru 8 as shown in FIG. 4 to indicate certain spaced points on the arcuate periphery of the main control member.

The main control member 35 is supported by the ball-like member 38 which is integral with the member 39. The member 39 is exteriorly threaded and extends through an interiorly threaded passage in the base member 30. The spacing of the ball-like member relative to the base member may be adjusted by the interiorly threaded lock nuts 41 (FIG. 5).

As shown in FIG. 5, the ball-like member 38 is received in a hearing or socket formed in the main control member and the fit between the ball-like member and the sides of the bearing may be adjusted by the element 40 which has an exteriorly threaded portion 40a received in an interiorly threaded passage in the main control member. Spaced orifices 40b (FIG. 8) are provided in the head of the element 40 to receive a tool for use in rotating 40 so as to accurately position it relative to the main control member and the ball-like member. Element 40 is locked in adjusted position by set screw 400. It will be noted that the lower end of the element 40v is concave and that it forms the upper part of the housing for the ball-like member.

The ball-like member 38 and its housing are included in the term universal joint" as used in this specification. a

Two spaced apart control elements 42 and 43 are provided. The control element 43 is connected to the operator or valve spool which controls the hydraulic motors for swinging the boom laterally and the control element 42 is connected to the operator which controls the hydraulic motor for moving the boom upwardly and downwardly as explained in more detail below.

The control elements 42 and 43 are provided with ball-like members 42a and 43a and adjustment members 42b and 43b including set screws 42i and 43i which are similar to the above described elements 38, 40 and 400.

The centers of the ball-like members 38, 42a and 430 are located substantially in a single plane (show in dotdash) which extends laterally through the main control member.

As shown in FIGS. 1, l3 and 14 a substantially horizontal plate member 45 is secured to the structure 31.

Referring to FIG. 13, the upper ends of the elements 420 and 430 are exteriorly threaded and these exteriorly threaded ends are received in interiorly threaded sockets in the enlarged portions 42d and 43d of the control elements. The operative length of the elements 42c and 43c may be adjusted by rotating the elements 42d and 43d relative to the elements 420 and 430, the holes 42h and 43h serving to receive a tool for rotating them. Then they may be locked in their adjusted positions by the lock nuts 42e and 43e.

The elements 42c and 430 are slidable in passages in the elements 42]" and 43f (FIG. 13) and their lower ends are attached to the ends of flexible cables 42g and 43g. The other ends of the flexible cables are attached to the boom lift valve spool 47 and to the boom swing valve spool 48 respectively. These valve spools are slidable longitudinally in the valve spool housing 49 as is well known in the art.

An interiorly threaded passage 100 (FIGS. 4 & 5) similar to the interiorly threaded passage 40a may be provided in the main control member opposite the element 42b and a corresponding opening 101 in the base member 30 may be provided. This passage and opening permit moving the elements 42 through 421' from their locations shown in FIGS. 4 and 5 to the passage 100 and opening 101 so that the action of the lever 33 reverses the operation of the BOOM UP" and BOOM DOWN valve spools if the operator so desires. Similarly the threaded passage to receive the handle of the lever 33 may be located where said threaded passage 100 is located and the passage 100 may be located where the threaded passage to receive the lever 33 is located in FIG. 4 with the opening 101 relocated beneath the passage 100. Then by moving the elements 43 through 431' from their locations shown in FIGS. 4, 13 and 14 tothe thus relocated passage and opening 100, 101, the action of the lever 33 reverses the operation of the SWING LEFT and SWING RIGI-IT valve spools.

The control mechanism includes means for preventing rotation of the main control member 35'about an axis which coincides substantially with the center of the ball-like member 38 and is substantially normal to the surface of the base member 30. In the embodiments of these views of the drawings, this would be the longitudinal axis of the member 39. As shown in FIGS. 4 to 7, this means comprises the U-shaped member 53 which is secured to the base member 30. This U-shaped member forms a longitudinal slot 530(FIG. 5A). The pin 54 secured to the main control member 35 projects later.- ally from the control member into this longitudinal slot. Consequently coaction between the pin and the sides of the slot prevents rotation of the main control member about said axis when the knob of the single control lever 33 is actuated. The control lever may be actuated to tilt the main control member about the center of the ball-like member 38 so that the main control member moves from the neutral position shown in FIG. 5, for example, to the BOOM DOWN position of FIG. 6 and to the BOOM UP position of FIG. 7. Other positions to'which the main control member may be titled andr'evolved will be described later in the specification.

Another embodiment of means for preventing rotation of the main control member is shown in FIGS. 9 and in which the member 56 projects laterally outwardly from the periphery of the main control member 35 and is provided with a ball-like member 56a at its end. The member 57projects upwardly from the base member and is provided with a ball-like member 570. These ball-like members are received in housings in the members 56b and 57b respectively which are attached at the ends of the link member 58. The members 56 and 57 are exteriorly threaded so' that the spacings of the ball-like members 56a and 57a from the main control member and the base member 30 may be adjusted.

Referring to FIGS. 4 and 5, an indicating ring 60 (which is optional) is mounted between the base member 30 and the main control member 35 by four collars 61 and four screws 62 which extend through spaced passages in the ring into interiorly threaded sockets in the base plate 30. This ring contains indicia which are opposite the indicating numerals l to 8 of the bevelled portion 35a of the main control member such as SWING LEFT opposite 1, SWING LEFT-BOOM DOWN opposite 2, BOOM DOWN opposite 3, etc. as shown in FIG. 4.

THE OPERATION OF THE EMBODIMENTS OF FIGS. 1 TO 10, 13 AND 14 I When it is desired to-move the boom downwardly, the main control member is titled about the ball-like member 38 in a direction so that the numeral 3 of the main control member is moved downwardly towards the BOOM DOWN" indication from the neutral position of FIG. 5 to the BOOM DOWN position of FIG. 6. This causes the control element 42 to actuate the operator 47 to the position shown in FIG. 14 so that oil flows from the pump to the port of the boom lift hydraulic motor which causes the boom to be moved downwardly and flow outwardly from the other port of the boom lift hydraulic motor to the tank. In this position of the main control member, the operator 48 is closed (FIG. 14) so that oil does not flow from the pump to the hydraulic motors for swinging the boom laterally.

When it is desired to move the boom upwardly, the main control member is titled about the ball-like member 38 in a direction so that the numeral 7 of the control member is moved downwardly towards the BOOM UP indication. This causes the control element 42 to actuate. the operator 47 so that oil flows from the pump to the port of the boom lift hydraulic motor which causes the boom to be moved upwardly and to flow outwardly from the other port of the lift hydraulic motor to the tank.

It will be noted that during each of these movements, the upper ends of the exteriorly threaded screws 65 are flush with the plane upper surface of the base member 30 and that they are held in such positions by the locknuts 65a so that the downward tilting movements of the main control member are arrested or stopped by engagement of the lower actuate peripheral edge 35c of the main control member with the ends of said screws 65. If it is desired to limit the amount of oil which is permitted to flowto the operative part of the hydraulic lift motor, one or both of these screws may be adjusted upwardly thus limiting the downward movement of the control element 42 and the longitudinal movements of the cable 423 and of the operator 47.

It is to be noted however that the screws 65 are optional and may be omitted, in which event, the downward movementsv of the main control member are limited or stopped by the upper plane surface of the base 30.

The provision of such guide or stop means for the tilting movement of the main control member is important because it prevents the exertion of loads or forces by the cables 42g, 43g, or by equivalent links which will be described below, upon the valve spools 47, 48, which are greater than required to extend or retract the valve spools so that the valve spools, cables, links and other associated members are not subjected to excessive wallowing or wear.

When it is desired to swing the boom to the left, the main control member is titled about the ball-like member 38 in a direction so that the numeral 1 of the main control member is moved downwardly towards the SWING LEFT indication; This causes the control element 43 to actuate the operator or valve spool 48 so that oil flows from the pump to the port of the hydraulic motor which causes the boom to be swung to the left and to flow outwardly from the other port of the hydraulic motor to the tank. Similarly when the main control member is titled so that the numeral 5 is moved downwardly towards the SWING RIGHT indication, the operator 48 is actuated so that oil flows from the pump to the port of the hydraulic motor which causes the boom to be swung to the right. As shown in FIG. 4, limiting screws 65 may be provided in the base member opposite each of the indicating numerals so that the longitudinal movements of the operator 48 for the swing hydraulic motor may be adjusted in the same manner as the movements of the operator 47.

When it is desired to swing the boom laterally to the left and simultaneously move the boom downwardly at substantially the same speeds, the main control member is tilted about the ball-like member 38 in a direction .50 that the number 2 is moved downwardly towards the SWING LEFT-BOOM DOWN indication on the ring until its arcuate periphery 35c engages the top of the limiting screw 65 which is beneath the numeral 2 position or the surface of the base 30 if the limiting screws are omitted. This causes the control elements 42, 43 and the operators 47, 48 to be moved to the positions shown in FIGS. 8 and 13 so that the flow of oil from the pump is split equally between the port for the hydraulic motor which causes the boom to swing left and the port of the hydraulic motor which causes the boom to move downwardly. Simultaneously, the ports of the hydraulic motors which permit oil to flow from the opposite ends of the cylinders of said hydraulic motors to the tank are opened by equal amounts.

When it is desired to swing the boom laterally to the left faster than the boom is moved downwardly, the main'control member is tilted in a direction so that its arcuate peripheral edge 35c makes contact with the surface of the base 30 at a point between the SWING LEFT indication and the BOOM DOWN indication but closer to the SWING LEFT indication than to the BOOM DOWN indication. Then, if the operator desires to increase the speed of the swing left motion and decrease the boom lowering motion, it is accomplished by revolving the main control member about the ball like member 38 so that the Contact point of the peripheral edge 35c of the main control member and the surface of the base 30' is moved to a location closer to the SWING LEFT indication.

When the boom is being moved downwardly fast enough and the boom is being swung left fast enough, the lever 33 is held in that position by the operator of the backhoe until the desired movements of the boom have been completed.

During such revolving movements of the main control member, the upper surface of the base 30 acts as a table or guide means upon which the arcuate peripheral edge 350 of the main control member revolves or rolls as the operator manually revolves the main control member about the ball-like member 38 to increase the flow of oil through the hydraulic motor which moves the boom downwardly. This automatically, simultaneously, proportionately and progressively increases the flow of oil to the hydraulic motor which swings the boom to the left. Accordingly, such increases and decreases of the flow of oil to the hydraulic motors is not dependent upon the operators guesswork or judgment but they are performed automatically by the control mechanism.

If it is desired to move the boom downwardly, faster than it is swung to the left, the main control member is tilted about the ball-like member 38 in a direction so that its arcuate peripheral edge makes contact with the surface of the base at a point between the BOOM DOWN" indication and the SWING LEFT indication but closer to the BOOM DOWN" indication. Then if the operator desires to increase the speed of the boom down motion the main control member is revolved about the ball-like member 38 so that the contact point between the peripheral edge of the main control member and the surface of the base is moved to a location closer to the BOOM DOWN" indication. When the boom is being moved downwardly fast enough and the boom is being swung left slowly enough, the lever 33 is held in that position by the operator of the backhoe until the desired movements of the boom have been completed.

Similarly automatic, proportionate and progressive increases or decreases of the flow of oil to and from the hydraulic motors for BOOM UP and SWING RIGHT and BOOM- UP and SWING LEFT" movements may be provided by revolving the main control member about the ball-like member 38 with its arcuate peripheral edge in rolling contact with the upper surface of the base 30. The means for preventing rotation of the main control member about the longitudinal axis of member 39 is believed to be essential during such revolving actuation of the main control member.

Should it be desired to operate the control mechanism without contact between the arcuate peripheral edge of the main control member and guide or stop means such as the upper surface of the base 30 this may be accomplished by moving the ball-like member 38 upwardly by adjustment of the lock nuts 41, in which event the valve spools 47, 48 will act as stops when they have been fully actuated in either direction.

THE EMBODIMENT OF FIG. 11

In FIG. 11 the ring 72 is mounted above the main control member 35 by a plurality of spaced posts or separators 73 which extend between it and the base member 30. This ring may also be secured to the top of the U-shaped member 53 which is similar in construction to the U-shaped member 53 shown in FIG. 5A of the drawings. The ring 72 serves'as an indicating ring similar to the ring and also as guide means similar to the upper plane surface of the base member 30 As shown in dot-dash lines in FIG. 11 the arcuate upper edge 35d of the periphery of the main control member 35 contacts the lower plane surface of the ring 72 when the main control member is tilted about the center of the ball-like member 38. It also is in rolling contact with that plane surface when the main control member is revolved about the ball-like member 38. Ad-

It will be obvious to persons skilled in the art that the embodiment of FIG. 11 functions in the same way as the embodiment of FIGS. 1 to l0, l3 and 14.

THE EMBODIMENT OF FIG. 12

In this embodiment the main control member 35 is provided with a portion 35b which is of reduced diameter. The ring 74 is similar to the ring 60 of the first embodiment but it is of reduced diameter and it functions not only to receive the indicia such as SWING LEFT, SWING LEFT-BOOM DOWN, BOOM DOWN," etc., but also as guide means for contacting the outer arcuate lower peripheral edge 3500f the main control member (as shown in dot-dash lines) to stop or limit the tilting movements of the main control member and to guide the main control member during revolving movements thereof about theball-like member 38.

It will be apparent to persons skilled in the art that the embodiment of FIG. 12 functions in the same manner as the embodiment of FIGS. 1 to l0, l3 and 14.

THE EMBODIMENTS OF FIGS. 15 and 16 member is tilted downwardly about the ball-like member 38 so that the numeral 1 is adjacent to the SWING LEFT" indication on the ring 60 (FIG. 4) and when the numeral 3 is moved downwardlyso that the numeral 3 is adjacent to the BOOM DOWN indication on the ring 60 there are full flows of the oil thru the respective operators for the hydraulic motors to cause full swing left and full boom downmovements of the boom respectively. However because substantially all of the peripheralarcuate edge of themain control member has been omitted from the locality thereof between the numerals '1 and 3 there is no arcuate peripheral edge for providing smooth rolling contact between the lower edge of the straight part 800 of the main control member and the upper plane surface of the base member during revolving movements of the main control member and consequently the operator of the backhoe must use his judgment to control the split of oil between the hydraulic motors when the main control member is revolved between the SWING LEFT and the BOOM DOWN positions. The same is true between the SWING RIGHT and the BOOM UP positions opposite numerals 5 and 7. However the same smooth progressive rolling contact between the arcuate peripheral portions 80a and 80b and the upper surface of the base is provided between the BOOM DOWN and SWING RIGHT positions (numerals 3, 4 and 5) and between BOOM UP and SWING LEFT positions (numerals 7, 8 and l) as in the embodiment of FIGS.

4 to 10. The embodiment of FIG. 16 is similar to the' embodiment of FIG. except that the arcuate portions 80c and 80f are shorter than the arcuate portions 80a and 80b and the straight portions 80g and 80h are longer than the straight portions 80c and 7 80d respectively.

- FIGS. 4 to 11 which extends for 360.

14 The dot-dash line 801' in FIG. 15 shows how the straight part 800 of the main control member may be modified as desired.

THE EMBODIMENT OF FIG. 17

In FIG. 17 the main control member 81 is provided with arcuate peripheral portions 81a and 81b which are substantially concentric with the center of the ball-like member 38 when viewed from the top, and the ends of these arcuate portions are connected by portions which terminate in the points 81c and 81d. With this modification the split of flow of oil thru the operators to the hydraulic motors is reduced between SWING LEFT and BOOM DOWN positions (numerals l and 3) and between the SWING RIGHT" and BOOM UP positions (numerals 5 and 7) because the lower edges of the points 810 and 81d come into contact with the upper plane surface of the base member in those positions and reduce the amounts of the longitudinal movements of the operators 47 and 48.

However the same type of rolling contact between the lower peripheral edges of the arcuate portions 81a and 81b and the upper surface of the base member 30 is provided when the main control member is revolved between the BOOM DOWN and SWING RIGHT positions (numerals 3, 4 and 5) and between the BOOM UP and SWING LEFT positions (numerals 7, 8 and l) as in the embodiment of FIGS. 4 tol0.

By varying the contours and the locations of the out- .wardly extending portions of the main control member THE EMBODIMENT OF FIGS. 18 and 19 In the embodiment shown in these views the arcuate peripheral portion of the main control member extends for about as compared to the arcuate peripheral portion of the main control member 35 of The supplemental combined, guide and indicating means 91 comprises, a top substantially semicircular member 91a, a substantially, verticalflange 91b and an outwardly extending substantially horizontal flange 910 which is attached to the base member 30.

A slot 53a is provided in the vertical flange 91b and it receives the pin 54 so this slot and pin function to prevent rotation of the main control member 90 about the axis of the member 39 in the same manner as the pin 54 and slot 53a (FIG. 5A) of the first embodiment.

When the main control member 90 is revolved about the ball-like member 38 from numerals 2 to l, to 8, to 7 to 6 (looking at FIG. 18), (SWING LEFT-BOOM DOWN to SWING RIGHT-BOOM UP) or vice versa the lower arcuate peripheral edge 350 of the main control member contacts and is guided by the upper plane surface of the base member 30.

On the other hand when the main control member 90 is revolved about the ball-like member 38 from the numerals 2 to 3, 3 to 4, 4 to 5, and 5 to 6 or vice versa looking at FIG. 4 the upper arcuate peripheral edge 35d of the main control member 90 contacts and is guided by the lower plane surface of the flange 91a. 

1. In a control mechanism comprising a base member, a main control member, means for supporting the main control member for tilting and revolving movements about a member which is spaced from the base member, means for preventing rotation of the main control member about an axis which coincides substantially with the center of said member about which the main control member is tiltable and revolvable and is substantially normal to the base member, at least two spaced apart control elements, means for pivotally securing corresponding ends of said control elements to said main control member at localities which are spaced from each other and from said means for supporting the main control member, means for connecting the opposite ends of said control elements to operators, and a control lever mounted on the main control member for tilting and revolving the main control member about said means for supporting the main control member thereby to actuate the control elements, wherein the improvement comprises, said means for preventing rotation of the main control member comprising a first member which projects upwardly from the base member at a locality located laterally of the main control member, a second member projecting laterally from the main control member, each of said projecting members being provided with a ball-like member at its outer end, and a link member connecting said projecting members by means of substantially spherical housings which receive said ball-like members.
 2. In a control mechanism comprising a base member, a main control member, means for supporting the main control member for tilting and revolving movements about a member which is spaced from the base member, means for preventing rotation of the main control member about an axis which coincides substantially with the center of said member about which the main control member is tiltable and revolvable and is substantially normal to the base member, at least two spaced apart control elements, means for pivotally securing corresponding ends of said control elements to said main control member at localities which are spaced from each other and from said means for supporting the main control member, means for connecting the opposite ends of said control elements to operators, and a control lever mounted on the main control member for tilting and revolving the main control member about said means for supporting the main control member thereby to actuate the control elements, wherein the improvement comprises, guide means for engagement with the main control member to guide its revolving movements and to limit its tilting movements about the means for supporting the main control member, said main control member comprising a substantially arcuate peripheral portion, and the guide means comprising a guide member attached to the base member for engagement with said substantially arcuate peripheral portion of the main control member, said guide member being located between the base member and the substantially arcuate peripheral portion of the main control member.
 3. A control mechanism according to claim 2, wherein said guide member comprises a plane surface.
 4. A control mechanism according to claim 2, wherein said guide member comprises at least one raised portion for engagement with the arcuate peripheral portion of the main control member.
 5. A control mechanism according to claim 2, wherein the substantially arcuate peripheral portion of the main control member extends for substantially 360*.
 6. A control mechanism according to claim 2, wherein the substantially arcuate peripheral portion of the main control member extends for about 180*.
 7. A control mechanism according to claim 2, wherein the main control member comprises a substantially arcuate peripheral portion and the guide means comprises a guide member attached to the base member for engageMent with said arcuate peripheral portion of the main control member, said guide member being located at the side of the main control member opposite the base member.
 8. A control mechanism according to claim 7, wherein said guide member comprises a plane surface.
 9. A control mechanism according to claim 7, wherein said guide member comprises at least one raised portion for engagement with the arcuate peripheral portion of the main control member.
 10. A control mechanism according to claim 7, wherein the substantially arcuate peripheral portion of the main control member extends for substantially 360*.
 11. A control mechanism according to claim 7, wherein the substantially arcuate peripheral portion of the main control member extends for about 180*.
 12. In a control mechanism comprising a base member, a main control member, means for supporting the main control member for tilting and revolving movements about a member which is spaced from the base member, means for preventing rotation of the main control member about an axis which coincides substantially with the center of said member about which the main control member is tiltable and revolvable and is substantially normal to the base member, at least two spaced apart control elements, means for pivotally securing corresponding ends of said control elements to said main control member at localities which are spaced from each other and from said means for supporting the main control member, means for connecting the opposite ends of said control elements to operators, and a control lever mounted on the main control member for tilting and revolving the main control member about said means for supporting the main control member thereby to actuate the control elements, wherein the improvement comprises, said main control member when viewed from the top comprising at least one arcuate portion which is substantially concentric with said means for supporting the main control member for revolving movement and at least one straight portion which intersects one end of said arcuate portion.
 13. In a control mechanism comprising a base member, a main control member, means for supporting the main control member for tilting and revolving movements about a member which is spaced from the base member, means for preventing rotation of the main control member about an axis which coincides substantially with the center of said member about which the main control member is tiltable and revolvable and is substantially normal to the base member, at least two spaced apart control elements, means for pivotally securing corresponding ends of said control elements to said main control member at localities which are spaced from each other and from said means for supporting the main control member, means for connecting the opposite ends of said control elements to operators, and a control lever mounted on the main control member for tilting and revolving the main control member about said means for supporting the main control member thereby to actuate the control elements, wherein the improvement comprises, said main control member comprising generally parallel upper and lower surfaces, said main control member comprising at least one substantially arcuate peripheral edge portion, and said control mechanism also comprising guide means for engagement with said arcuate peripheral edge portion to guide said revolving movements and to limit said tilting movements of said main control member about said means for supporting it.
 14. A control mechanism according to claim 13, wherein said guide means comprises a portion of the base member located below said arcuate peripheral edge portion.
 15. A control mechanism according to claim 13, wherein said guide means comprises at least a portion of the upper surface of the base member.
 16. A control mechanism according to claim 13, wherein said guide means comprises a member attached to the base member and located above the upper surface of the maiN control member.
 17. A control mechanism according to claim 13, wherein said substantially arcuate peripheral edge portion extends for substantially 360*.
 18. A control mechanism according to claim 13, wherein said substantially arcuate peripheral edge portion of the main control member extends for only about 180*.
 19. A control mechanism according to claim 13, wherein said guide means comprises at least one raised portion for engagement with said arcuate peripheral edge portion of the main control member.
 20. A control mechanism according to claim 13, wherein the means for supporting the main control member for revolving movement comprises a universal joint associated with the end of a support member.
 21. A control mechanism according to claim 20, wherein the universal joint comprises a ball-like member.
 22. A control mechanism according to claim 21, wherein said ball-like member is integral with the upper end of said extension of the means for supporting the main control member and, when the main control member is in its neutral position, at least the lower portion of said ball-like member which is adjacent to the upper end of said extension is journaled in a generally bowl-shaped bearing formed in the body of the main control member and said extension extends downwardly from and substantially normal to the lower surface of the main control member.
 23. In a control mechanism comprising a base member, a main control member, means for supporting the main control member for tilting and revolving movements about a member which is spaced from the base member, means for preventing rotation of the main control member about an axis which coincides substantially with the center of said member about which the main control member is tiltable and revolvable and is substantially normal to the base member, at least two spaced apart control elements, means for pivotally securing corresponding ends of said control elements to said main control member at localities which are spaced from each other and from said means for supporting the main control member, means for connecting the opposite ends of said control elements to operators, and a control lever mounted on the main control member for tilting and revolving the main control member about said means for supporting the main control member thereby to actuate the control elements, wherein the improvement comprises, said main control member comprising generally parallel upper and lower surfaces, the lower surface facing said base member and being spaced a substantial distance above it, whereby a substantial gap is provided between it and the upper surface of said base member when said main control member is in its neutral non-tilted position, said upper surface of the main control member being free from engagement with any casing at all times, the upper ends of said means for pivotally securing corresponding ends of said control elements being attached to said main control member, said means comprising extensions which pass downwardly through said gap and through openings in the base member, said means for supporting the main control member being attached to said main control member and comprising an extension member which passes downwardly through said gap to the base member, and means associated solely with said extension member of said means for supporting the main control member and with said base member for substantially adjusting the size of the space between the lower surface of said main control member and the upper surface of said base member, whereby the lengths of the linear movements of said control elements caused by tilting and revolving said main control member about said means for supporting the main control member may be substantially adjusted so that operators of different linear strokes may be used without the use of other adjusting means.
 24. A control mechanism according to claim 23, wherein said means for substantially adjusting the size of said space compriseS an exteriorly threaded portion of said extension member of said means for supporting the main control member which extends into a passage in the base member and at least one interiorly threaded lock nut which receives a portion of said exteriorly threaded portion.
 25. A control mechanism according to claim 23, wherein said control member comprises at least one substantially arcuate peripheral edge portion, and said control mechanism also comprises guide means for engagement with said arcuate peripheral edge portion to guide said revolving movements and to limit said tilting movements of said main control member about said means for supporting the main control member.
 26. A control mechanism according to claim 25, wherein said guide means comprises a portion of the base member located below said arcuate peripheral edge portion.
 27. A control mechanism according to claim 25, wherein said guide means comprises a guide member attached to the base member and located above the upper surface of the main control member.
 28. A control mechanism according to claim 25, wherein said guide means comprises at least one raised portion for engagement with said arcuate peripheral edge portion of the main control member.
 29. A control mechanism according to claim 28, wherein said guide means comprises means for adjusting the height of said raised portion.
 30. A control mechanism according to claim 25, wherein the means for supporting the main control member for revolving movement comprises a universal joint associated with the end of a support member.
 31. A control mechanism according to claim 30, wherein the universal joint comprises a ball-like member.
 32. A control mechanism according to claim 23, wherein the means for supporting the main control member for revolving movement comprises a ball-like member integral with the upper end of said extension of the means for supporting the main control member, said ball-like member being journaled in a bearing formed in the body of the main control member.
 33. A control mechanism according to claim 32, wherein a portion of said bearing comprises movable means for adjusting the fit between the ball-like member and the bearing.
 34. A control mechanism according to claim 33, wherein said bearing comprises a generally U-shaped socket in the body of the main control member, said movable means for adjusting the fit between the ball-like member and the bearing comprising an exteriorly threaded movable member which extends into an interiorly threaded portion of said socket, the lower end of said movable member comprising an arcuate wall portion which cooperates with an arcuate wall portion of the lower portion of the socket to receive said ball-like member, the upper portion of said movable member being exposed above said upper surface of the main control member, and means on said upper portion of said movable member for use in rotating said movable member thereby to adjust the clearance between its lower end and the ball-like member.
 35. A control mechanism according to claim 34, wherein said upper portion of said movable member comprises means for releasably locking said movable member in adjusted position.
 36. A control mechanism according to claim 35, wherein said locking means comprises an exteriorly threaded screw extending into an interiorly threaded passage in said upper portion of said movable member for frictionally engaging said upper surface of the main control member.
 37. A control mechanism according to claim 32, wherein each of said means for pivotally securing corresponding ends of said control elements to said main control member comprises a ball-like member integral with the upper end of an extension of said means for connecting said control element to an operator, each said ball-like member also being journaled in a bearing formed in the body of the main control member, and said control lever is secured solely to the main control member and free from attachment to said ball-like member which is Integral with the upper end of said extension of the means for supporting the main control member, whereby turning movements of said control lever relative to the main control member do not alter the relationships of said control element ball-like members, said ball-like member of said means for supporting the main control member and said means for preventing rotation of the main control member with respect to a plane which is generally parallel to said upper and lower surfaces of the main control member or with respect to each other, but the main control member and said control element ball-like members are moved by tilting and revolving movements of the main control member about said ball-like member of said means for supporting the main control member.
 38. In a control mechanism comprising a base member, a main control member, means for supporting the main control member for tilting and revolving movements about a member which is spaced from the base member, means for preventing rotation of the main control member about an axis which coincides substantially with the center of said member about which the main control member is tiltable and revolvable and is substantially normal to the base member, at least two spaced apart control elements, means for pivotally securing corresponding ends of said control elements to said main control member at localities which are spaced from each other and from said means for supporting the main control member, means for connecting the opposite ends of said control elements to operators, and a control lever mounted on the main control member for tilting and revolving the main control member about said means for supporting the main control member thereby to actuate the control elements, wherein the improvement comprises, said main control member comprising generally parallel upper and lower surfaces, said main control member comprising at least one substantially arcuate peripheral edge portion, said control mechanism also comprising guide means for engagement with said arcuate peripheral edge portion to guide said revolving movements and to limit said tilting movements of said main control member about said means for supporting it, each of said means for pivotally securing corresponding ends of said control elements to said main control member comprising a ball-like member integral with the upper end of an extension of said means for connecting said control element to an operator and, when the main control member is in its neutral position, at least the lower portion of said ball-like member which is adjacent to the upper end of said extension is journaled in a generally bowl-shaped bearing formed in the body of the main control member and said extension extends downwardly from and substantially normal to the lower surface of the main control member.
 39. A control mechanism according to claim 38, wherein a portion of said bearing comprises movable means for adjusting the fit between the ball-like member and the bearing.
 40. A control mechanism according to claim 39, wherein said bearing comprises a generally U-shaped socket in the body of the main control member, said movable means for adjusting the fit between the ball-like member and the bearing comprising an exteriorly threaded movable member which extends into an interiorly threaded portion of said socket, the lower end of said movable member comprising an arcuate wall portion which cooperates with an arcuate wall portion of the lower portion of the socket to receive said ball-like member, the upper portion of said movable member being exposed above said upper surface of the main control member, and means on said upper portion of said movable member for use in rotating said movable member thereby to adjust the clearance between its lower end and the ball-like member.
 41. A control mechanism according to claim 40, wherein said upper portion of said movable member comrpises means for releasably locking said movable member in adjusted position.
 42. A contRol mechanism according to claim 41, wherein said locking means comprises an exteriorly threaded screw extending into an interiorly threaded passage in said upper portion of said movable member for frictionally engaging said upper surface of the main control member. 